Solid Roller vs. Hyd. Roller - Pros/Cons?

[Barry_R]

I have an open invitation to other FE builders to bring a build down to my dyno for comparison sake. Mr Lykins has expressed interest but the geography gets in the way.

My machine is a somewhat older (late 90s vintage) DTS8800 (also sold as a DTS 4000 at one point in time). It was originally purchased and installed at Wheel to Wheel Powertrain and calibrated/certified for use in GM OEM engine development work. When "The Wheel" went out of business as a result of the economy meltdown this dyno was sold at auction and I eventually acquired it along with virtually everything in the cell.

I have had the unique opportunity to test several engines on this machine - and then transport them to another facility to run them again. The EMC uses a DTS Powermark series dyno pair that is calibrated by the DTS engineering group before the contest, in the middle of the contest, and at the end of the contest. It should be obvious that - with +/-50 engine builders involved and a good amount of prize money and media visibility at stake, the accuracy of the results is pretty critical.

So far, engines tested on my equipment have generally been extremely close to the contest numbers - within one or two percent - with mine being slightly lower. Well within expectations given the differences in room layout - mine has a room mandated 90 degree turn in the exhaust at the back of the cell. Jim Stykes has a nearly identical "sister dyno" to mine, also used by GM, which I used prior to getting my own. His reads slightly higher, but the exhaust runs straight out the back wall. Mike Phillps, the Buick guy, has another similar one and his numbers are virtually identical to his contest numbers. You could toss a blanket over all our variability.

I have run a great number of 482 inch FE engines on this machine. While I have admittedly "squinted" at some of his results (we are competitors after all) Brett's 638 number on this 482" seems pretty realistic considering the parts employed. We've done several solid rollers packages that fell in between 611 and 650ish. I think that with the singular exception of my Engine Masters stuff, the highest hydraulic roller I have was a much larger 527 incher with power in the 620+ range.

This is a loooong way of pointing out that I agree with Mr. Lykins 100% on some of the dyno numbers I see tossed around. When I see values that are way, way out of context to those I can generate using comparable components I need to question the source data. Torque per cubic inch values that approach the EMC level 1.4 per cube are generally unrealistic with "normal" parts. I KNOW what it takes to get there and you simply ain't gonna reach that level with normal bolt it together type parts no matter how good you are.